1. Field of Invention
The invention relates to a stamp unit and method of manufacturing a stamp unit having a holding unit which holds a stamp material. The stamp unit is positionable in a stamp manufacturing device where the holding unit is pressed while a stamp is manufactured from the stamp material. More specifically, the invention relates to providing a uniform pressure applied to a stamp material during manufacture regardless of the size of the stamp material.
2. Description of Related Art
The conventional stamp unit comprises a grip, a holder and a skirt member. The holder member is connected to the grip member, and is capable of moving vertically within the skirt member. The stamp material is thermally adhered to a lower end portion of the holder member. In such a conventional stamp unit, the stamp material is formed of two layers. The lower layer is made of a soft porous resin formed with a light energy absorption material, such as carbon black, dispersed therein. The upper layer, which supplies ink to the lower layer and is capable of pressing the lower layer uniformly, is made of a hard porous resin.
In the case of manufacturing a stamp, a roll-shaped transparent film is transported into the stamp manufacturing device. Then, character and image data is printed by a thermal head and ink transfer ribbon onto the transparent film to create a positive original film. The holder member is placed into the stamp manufacturing device so that the positive original film and the stamp material oppose each other with a transparent acrylic plate between them. When an irradiation unit, such as a xenon tube, emits light, the lower layer of the stamp material is illuminated or exposed through the positive original film. Only the portion which is illuminated through the non-printed or transparent portion of the positive original film is melted and solidified by the heat generated by the light energy absorption material that is, the carbon black, to create a seal so that ink does not permeate. On the other hand, the portion which is not illuminated, melted or solidified forms an image, such as the characters and symbols on the positive original film. Thus, the stamp is manufactured on the lower layer, and contains sealed and unsealed portions according to the desired pattern.
An ink pack is stored in an ink pack storing portion within the holder member. The ink pack storing portion has an uneven bottom formed in a lattice shape. The ink pack is opened when it is sandwiched and pressed between the uneven bottom and a plate attached to the grip member, by moving the grip member downward. Ink flowing from the ink pack is stored in the upper and lower layers of the stamp material. The ink flows out from the unsealed portion, but does not flow out from the sealed portion.
In the case of printing characters using the stamp unit, the grip member is moved downward to place the skirt member at the desired position on a printing sheet. The grip member moves the holder member downward within the skirt member so that the stamp material is pressed against the printing sheet. Ink attaches to the printing sheet through the unsealed portion of the stamp material so that various kind of images, such as characters and symbols, can be printed.
As described above, the stamp unit, including the holding unit, the skirt member and the grip member, are placed in the stamp manufacturing device where the holding unit is pressed while a stamp is manufactured. In such a case, it is necessary to provide a holding unit storing portion which can store the holding unit. Accordingly, it is necessary to provide enough space to insert the various members associated with the stamp unit.
Therefore, a stamp unit has been proposed, wherein only the stamp material and the holder member are placed into the stamp manufacturing device. After a stamp is manufactured with the stamp manufacturing device, the holder member which holds the stamp material, is inserted into the skirt member and attached to the grip member so as to be movable vertically within the skirt member.
Such a stamp manufacturing device has an irradiation unit on which the holding unit comprising at least the stamp material and the holder member is placed. A presser unit comprising a lid encloses the holding unit within the stamp manufacturing device, and presses the holding unit, and in particular the stamp material, at a predetermined position onto the irradiation unit, when the lid is closed.
However, in the conventional device, the holding unit that is placed into the stamp manufacturing device has a fixed height regardless of the stamp material size. However, the stamp material has to be pressed uniformly onto the irradiation unit while a stamp is being produced. When the holding unit is placed into the stamp manufacturing device and the lid is closed, the holding unit is pressed against the irradiation unit. A reaction force then acts on the irradiation unit and the presser unit in proportion to the stamp material size. A large reaction force causes portions of the irradiation unit and the presser unit to bend. This bending leads to a reduction in the pressure urging the stamp material against the irradiation unit, reducing the image quality of the manufactured stamp.
Therefore, it is an object of the invention to solve the above-mentioned problem, and to provide a method of manufacturing a stamp unit where the pressure on a stamp material is uniform regardless of the size of the stamp material where a holding unit having a holder member holds the stamp material, and the holding unit is placed into a stamp manufacturing device and pressed to manufacture a stamp from the stamp material.
In order to accomplish the object of the invention, the height of the holding unit is heightened in proportion to the stamp material size. That is, even if the stamp material is pressed with a fixed pressure, the reaction force differs according to the stamp material size. In response to the reaction force, portions of an irradiation unit and a presser unit bend in proportion to the reaction force.
By changing the height of the holding unit, the stamp material can be pressed uniformly onto an irradiation unit because the bending of the presser unit and irradiation unit is eliminated.
Preferably, the stamp material of the stamp unit comprises an elastic and transformable soft porous resin having a light energy absorption material at a lower end portion. The elastic and transformable soft porous resin projects from the lower edge of the holder member. In such a holding unit, it is effective to heighten the holding unit in proportion to the stamp size as the reaction force differs according to the stamp size.
Further, according to a preferred embodiment of the invention, the stamp unit comprises a skirt member, a holder member movably disposed within the skirt member for movement in an up and down (defined as axial) direction and configured to hold a stamp material at a lower end portion, and a grip member that moves the holder member downward within the skirt member. The holding unit includes the holder member and the stamp material. Because of the small size of the holding unit, the stamp material can be pressed properly, and the stamp manufacturing device can be miniaturized. Further, positioning grooves and marks for detecting the stamp size can be provided on the holder member, which is inserted within the skirt member, and do not effect its outward appearance.
The stamp manufacturing device into which the holding unit is placed preferably includes an original film making unit, an irradiation unit and a presser unit.
The stamp manufacturing device is easily affected by the reaction force, as the holding unit is sandwiched and pressed between the irradiation unit and the presser unit. The holding unit can be pressed uniformly by changing its height, thereby, adjusting the pressure on the stamp material.